Endoscopy enables high-resolution visualization of tissue texture and geometry and is a critical step in many clinical workflows, including diagnosis and treatment planning for cancers in the nasopharynx. For example, nasopharyngoscopy is a commonly used technique for nasopharyngeal cancer diagnosis and treatment planning. For radiotherapy, the planning requires tumor localization. Although nasopharyngoscopy can provide a direct, high-contrast, high-resolution visualization of a patient's interior tissue surface, it has a weakness for tumor localization in that it does not provide precise 3D spatial information. Thus, an endoscopic video does not provide its information in 3D space, making it difficult to use in tumor localization, and it is inefficient to review.